Heretofore, in order to improve serious states of patients with renal failure, patients developing hyperhydration due to chemical feeding after an operation, and the like, hemodialysis or blood filtration using a blood purification device has been performed. In order to supply a fresh dialysate to a blood purifier and discharge a used dialysate from a blood purifier, one utilizing a reciprocating pump capable of simultaneously performing the supply of a fresh dialysate and the discharge of a used dialysate is known heretofore (Patent Literature 1, Patent Literature 2).
Moreover, a plunger pump not requiring a valve for extracting the air in a dialysate has also been suggested as a reciprocating pump.
Known reciprocating pumps additionally require a water removing pump and a pressurization pump in order to perform water removal and backfiltration, and thus have posed a problem of an increase in cost. Other reciprocating pumps described previously do not simultaneously perform the supply of a fresh dialysate and the discharge of a used dialysate. Therefore, the reciprocating pumps need to be improved so as to simultaneously perform the supply of a fresh dialysate and the discharge of a used dialysate. Moreover, a plunger pump which enables the supply of a fresh dialysate without pulsation to a blood purification device has been desired.